<template>
  <div class="ScaleBox"
       ref="ScaleBox"
       id="ScaleBox"
       :style="{
  width: width + 'px',
  height: height + 'px',
}">
    <slot></slot>
  </div>
</template>

<script>

export default {
  name: "ScaleBox",
  props: {},

  data () {
    return {
      scaleX: 0,
      scaleY: 0,
      width: 1920,
      height: 1080,
    };
  },
  mounted () {
    this.setScale();
    window.addEventListener("resize", this.setScale);
  },
  methods: {
    getScale () {
      // 固定好16：9的宽高比，计算出最合适的缩放比
      const { width, height } = this;
      const wh = window.innerHeight / height;
      const ww = window.innerWidth / width;
      //console.log(ww < wh ? ww : wh);

      return { x: ww, y: wh }
      //return ww < wh ? ww : wh;
    },
    setScale () {
      // 获取到缩放比例，设置它
      this.scaleX = this.getScale().x;
      this.scaleY = this.getScale().y;
      if (this.$refs.ScaleBox) {
        this.$refs.ScaleBox.style.setProperty("--scaleX", this.scaleX);
        this.$refs.ScaleBox.style.setProperty("--scaleY", this.scaleY);
      }
    },
    debounce (fn, delay) {
      const delays = delay || 200;
      let timer;
      return function () {
        const th = this;
        const args = arguments;
        if (timer) {
          clearTimeout(timer);
        }
        timer = setTimeout(function () {
          timer = null;
          fn.apply(th, args);
        }, delays);
      };
    },
  },
};
</script>

<style lang="scss" scoped>
#ScaleBox {
  --scaleX: 1;
  --scaleY: 1;
}
.ScaleBox {
  position: absolute;
  transform: scale(var(--scaleX), var(--scaleY)) translate(-50%, -50%);
  display: flex;
  flex-direction: column;
  transform-origin: 0 0;
  left: 50%;
  top: 50%;
  // transition: 0.3s;
  z-index: 999;
  background-color: rgba(0, 16, 57, 1);
  // background: linear-gradient(180deg, #01369c, #164dba 56%, #00236a);
  // background: rgba(255, 0, 0, 0.3);
}
</style>